U.S. patent application number 11/634539 was filed with the patent office on 2007-07-12 for circular saw.
Invention is credited to Sion Netzler, Neil Walmsley, Mike Wilson.
Application Number | 20070157781 11/634539 |
Document ID | / |
Family ID | 36178042 |
Filed Date | 2007-07-12 |
United States Patent
Application |
20070157781 |
Kind Code |
A1 |
Wilson; Mike ; et
al. |
July 12, 2007 |
Circular saw
Abstract
A circular is provided which can operate in two modes. In a
first mode, the circular saw operates in a conventional manner; in
a second mode the circular saw can turned through 90.degree. to
operate in an undercutting mode, for undercutting a wall mounted
door, for instance. To achieve this, the blade shroud comprises an
outer surface facing away from the saw's motor housing which is
flat for engagement with a floor surface or a guide rail.
Advantageously, the outer surface might comprise a groove or
channel arranged to cooperate with a guide rail rib.
Inventors: |
Wilson; Mike; (Crook,
GB) ; Walmsley; Neil; (Ferryhill, GB) ;
Netzler; Sion; (Newton Aycliffe, GB) |
Correspondence
Address: |
Mehul R. Jani;Black & Decker Corporation
Mail Stop TW199
701 E. Joppa Rd
Towson
MD
21286
US
|
Family ID: |
36178042 |
Appl. No.: |
11/634539 |
Filed: |
December 6, 2006 |
Current U.S.
Class: |
83/469 |
Current CPC
Class: |
Y10T 83/768 20150401;
B27B 5/08 20130101; B27B 9/04 20130101; B27G 19/04 20130101 |
Class at
Publication: |
083/469 |
International
Class: |
B23D 19/00 20060101
B23D019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 8, 2005 |
EP |
05111837.0 |
Claims
1. A manually operable electrically powered tool, comprising: an
electric motor disposed in a housing, said motor being mechanically
coupled to a spindle having an axis of rotation; a blade clamp
attached to the spindle and being arranged to clamp a saw blade in
a manner allowing the saw blade to rotate in a plane of rotation; a
shroud for accommodating the blade clamp and a portion of a saw
blade, said shroud comprising an outer surface facing away from the
motor housing; and a base plate arrange to engage with a workpiece
during use, said base plate comprising an opening through which a
portion of the saw blade can extend to engage the workpiece,
wherein the shroud outer surface is substantially flat and
substantially parallel to the plane of rotation thereby allowing
the saw to operate in a horizontal cutting mode when the saw is set
on the shrouds outer surface.
2. The tool of claim 1, wherein the shroud comprises a guide
arranged to couple with a guide rail disposed on a planar surface
such that, when the saw is disposed on a guide rail with the guide
coupled to a guide rail, the plane of rotation is parallel with the
planar surface.
3. The tool of claim 2, wherein the guide comprises a channel
disposed on the outer surface to cooperate with a rib disposed on a
guide rail.
4. The tool of claim 3, wherein the channel extends along the outer
surface in a longitudinal direction such that either end of the
channel is open.
5. The tool of claim 1, wherein the housing is pivotably coupled to
the base plate.
6. The tool of claim 5, further comprising a resilient member
arranged to urge the housing away from the base plate.
7. The tool of claim 1, wherein the shroud comprises inner and
outer portions, the outer surface is disposed on the outer portion
of the shroud, and said outer portion is moveable between a first
and second position with respect to the housing.
8. The tool of claim 7, wherein the outer portion is disposed on a
guide member arranged such that the outer surface is parallel to
the plane of rotation when the outer surface is in either the first
or second position.
9. The tool of claim 7, further comprising a resilient member
disposed between the inner and outer portions of the shroud.
10. The tool of claim 7, wherein the inner and outer portions of
the shroud overlap thereby accommodating a saw blade disposed on
the blade clamp when the outer portion of the shroud is in the
first or second position.
11. The tool of claim 7, further comprising a shim having a
predetermined thickness, said shim being disposable between the
inner and outer portions of the shroud.
12. The tool of claim 7, further comprising a shim having a
predetermined thickness, said shim being disposable between the
outer surface and a guide rail.
13. The tool of claim 7, further comprising a shim having a
predetermined thickness, said shim being disposable between the
guide rail and a surface having the guide rail disposed
thereon.
14. A manually operable electrically powered circular saw,
comprising: a housing having a motor disposed therein, said motor
being mechanically coupled to a spindle having an axis of rotation;
a blade clamp attached to the spindle and being arranged to clamp a
saw blade in a manner allowing the saw blade to rotate in a plane
of rotation; and a blade shroud arranged to accommodate a portion
of saw blade disposed on the spindle, wherein the blade shroud has
an outer surface facing away from the housing, said outer surface
being substantially flat.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to European Patent
Application No. EP 05111837.0, filed Dec. 8, 2005. The entire
contents of that application are expressly incorporated herein by
reference thereto.
FIELD OF THE INVENTION
[0002] The present invention relates to an electrically powered
manually operable power tool. In particular, the present invention
relates to a circular saw which includes means to allow for
additional operations such as undercutting.
BACKGROUND OF THE INVENTION
[0003] Circular saws are well known power tools, generally used to
cut straight edged cuts in wood, lumber or sheet metal. Typically,
a circular saw comprises a housing mounted on a base plate. An
electric motor and gearbox are disposed in the housing. An output
spindle is mechanically coupled to the motor via the gearbox such
that activation of the motor causes the spindle to rotate. A blade
mount is attached to the output spindle for mounting a circular saw
blade thereon. When attached to the spindle, the blade extends
through an aperture in the base plate. A handle is provided for
manual guidance of the saw.
[0004] The base plate may include a channel running along the
underside of the base plate and parallel to the plane in which the
blade rotates. The channel is arranged to engage with a guide rail
which comprises a rib having the same width dimensions as the
channel. Thus, when the saw is disposed on the guide rail and a
portion of the rib is accommodated by the channel, the saw's
direction of cut can be guided by the rail. Such an arrangement is
disclosed in EP 0246417.
[0005] GB 1427700 describes a device for trimming the lower edge of
a door. The device comprises a base member with support means
carrying a motor for driving a rotary abrading tool about a
vertical axis, and adjacent the base member. The base member
engages with a floor next to a door and thereby enables the device
to be moved along the floor alongside a mounted door for trimming
its lower edge. The support means is a plate which is vertically
adjustable by means of nuts threaded on studs secured to the base
member.
[0006] GB 974674 describes a portable saw assembly which comprises
a spindle mounted in a body portion having at least one handle and
is, at one end, adapted to carry a circular saw blade and, at the
other end, adapted to be connected to a power driving means, such
as a portable electric drill. A gauge-base is adjustably mounted on
the body portion for movement towards and away from the blade, the
gauge-base serving to support the assembly for movement over a
supporting surface with the blade within a minimum clearance
distance of the surface.
[0007] U.S. Pat. No. 4,273,016 describes a template used in
assisting in cutting off a bottom of a door so that the bottom of
the door is parallel with the floor, but is raised a sufficient
distance from the floor to allow a floor covering to be installed
on the floor has an elongated member sized to fit across the width
of one of the face surfaces of the door.
[0008] U.S. Pat. No. 4,233,954 describes a portable concrete pile
cutting device which comprises a support collar adapted to be
removably mounted in supported annular location about a concrete
pile, at least one pile cutting assembly mounted for reciprocation
on the collar, and means located on the collar for the support of
the pile cutting assembly.
[0009] Devices described in the prior art require means for
mounting, or holding a saw onto the object being cut.
[0010] Embodiments of the present invention provide a manually
operated hand held circular saw which can operate in a conventional
manner, and which is easily adapted to operate for undercutting
doors, or the like. Thus, a circular saw is provided wherein the
blade shroud has a flat outer surface facing away from the motor
housing and on which the saw can rest, either on the floor adjacent
a door, or on a guide rail disposed on the floor.
BRIEF SUMMARY OF THE INVENTION
[0011] More specifically, the present invention provides a manually
operated electrically powered circular saw, comprising an electric
motor disposed in a housing, said motor being mechanically coupled
to a spindle having an axis of rotation, a blade clamp attached to
the spindle and being arranged to clamp a saw blade whereby, during
use, a saw blade disposed in the clamp can rotate in a plane of
rotation, a shroud for accommodating the blade clamp and a portion
of a saw blade, and a base plate arrange to engage with a workpiece
during use, said base plate comprising an opening through which a
portion of the saw blade can extend to engage the workpiece,
wherein the shroud comprises an outer surface facing away from the
motor housing, said outer surface being flat and parallel to the
plane of rotation thereby allowing the saw to operate in an
undercutting mode when the outer surface is rested on a floor
surface next to a door.
[0012] In the undercutting mode, the saw can be orientated on the
side of the shroud, that is resting on the outer surface of the
shroud, such that the base plate is vertical and saw blade can
extend from the base plate and rotate in a horizontal plane (when
the shroud is resting on a horizontal surface, such as a floor). In
this manner, for example, a circular saw embodying the present
invention can be disposed on the floor next to a door and
orientated in a way which allows the saw to undercut the door.
Furthermore, the phrase undercutting mode is not meant to limit the
scope of operation to just undercutting doors; other applications
will be envisaged by the skilled person, such as trimming a
skirting board or a dado rail disposed on a wall, for example.
[0013] Preferably, the shroud comprises a guide means arranged to
couple with a guide rail disposed on a planar surface such that,
when the saw is disposed on a guide rail with the guide means
coupled to a guide rail, the plane of rotation is parallel with the
planar surface. Thus, the saw embodying the present invention can
be located on a guide rail for improved accuracy of cutting.
[0014] Preferably, the guide means comprises a channel disposed in
the outer surface for engagement with a cooperating rib disposed on
a guide rail. Thus, the saw can be located on, and guided by a
conventional guide rail.
[0015] Preferably, the channel extends along the outer surface in a
longitudinal direction such that either end of the channel is open.
Thus, the saw is free to move along the length of the guide rail,
during use.
[0016] Preferably, the housing is pivotably coupled to the base
plate. Thus, the depth of cut achieved by the blade is
adjustable.
[0017] Preferably, a resilient member is arranged to urge the
housing away from the base plate. Thus, the present invention can
provide a plunge-action circular saw thereby improving the ease of
use of the saw.
[0018] Preferably, the shroud comprises inner and outer portions,
the outer surface is disposed on the outer portion of the shroud,
and said outer portion is moveable between a first and second
position with respect to the housing. Thus, a means of adjusting
the position of the saw blade relative to the floor or guide rail
is provide for the saw, when operating in the door cutting mode. In
other words, the distance between the plane of rotation and the
outer surface can be adjusted.
[0019] Preferably, the outer portion is disposed on a guide member
arranged such that the outer surface is parallel to the plane of
rotation when the outer surface is in either the first or second
position. The guide member acts to maintain the orientation of the
outer surface as it is moved between the first and second positions
thereby preventing, or aiding in the prevention of the saw blade
becoming misaligned with the plane of the outer surface.
[0020] Preferably, a bellows member is disposed between the inner
and outer portions and the shroud. Alternatively, the inner and
outer portions of the shroud can be arranged to overlap thereby
accommodating a saw blade disposed on the blade clamp when the
outer portion of the shroud is in the first or second position. The
bellows member or overlapping portions of the shroud act to retain
any saw dust or debris within the shroud; the shroud remains a
closed hood over the saw blade.
[0021] Preferably, a shim having a predetermined thickness is
provided, said shim being disposable, either between the inner and
outer portions of the shroud, or between the outer surface and a
guide rail, or between the guide rail and floor surface on which
the rail is disposed. The shim provides an alternative means of
adjusting the distance between the plane of rotation and the outer
surface, as described above.
[0022] Preferably, the base plate comprises a channel arranged to
cooperate with a guide rail. Thus, the guide rail can be used
conventionally and in the door cutting modes.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0023] Embodiments of the present invention are now described by
way of example, and with reference to the accompanying
drawings.
[0024] FIG. 1 is a schematic diagram of a circular saw embodying
the present invention and operating in a conventional manner;
[0025] FIG. 2 shows the circular saw of FIG. 1 operating in a door
cutting mode;
[0026] FIG. 3 shows a schematic diagram of a portion of a saw
embodying the present invention;
[0027] FIG. 4 shows a schematic diagram of a portion of an
alternative saw embodying the present invention; and
[0028] FIG. 5 shows a schematic diagram of an embodiment of the
present invention undercutting a door.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Referring to FIG. 1, a circular saw 10 embodying the present
invention is shown. The saw comprises a housing 12 having a motor
14 and a gearbox 16 disposed therein. The motor is coupled to an
output shaft 18 via the gearbox. A blade clamp 20 is disposed on
the end of the output shaft extending inside a shroud or cowl 22. A
circular saw blade 24 is shown attached to the spindle by the blade
clamp. A handle 26 is provided to aid the user in operating the
saw. A switch is disposed at a convenient location so that the user
can activate the electric motor 14 while gripping the handle. The
saw 10 further comprises a base plate 28 which is coupled to the
housing and/or the cowl 22. The motor can be powered by either
electricity or by a battery pack.
[0030] FIG. 1 shows the saw embodying the invention being disposed
in a conventional manner on a workpiece WP. The saw is arranged to
cut the workpiece. A guide rail 30 is disposed between the base
plate 28 and the workpiece WP. The guide rail comprises a
longitudinal rib 32 which is arranged to cooperate with a channel
34 in the base plate. Thus, the location and direction of the cut
intended to be made on the workpiece by the saw is determined by
the position of the guide rail on the workpiece. Of course, it is
not necessary to use a guide rail in this manner--the operator
might prefer to cut the workpiece without using a guide rail.
[0031] The blade shroud 22 comprises an outer surface 36 which
faces away from the motor housing. This surface is substantially
flat. By "substantially flat" we mean that the surface is arranged
to have a flat profile, although there might be patterns or surface
decoration (such as profiled or embossed trademark) on the surface;
the surface 36 has a general configuration that is flat or
planar.
[0032] A shroud channel 38 is disposed in a longitudinal direction
on the shroud outer surface 36. The shroud channel 38 has the same
cross-sectional dimensions as the channel 34 in the base plate.
Thus, the shroud channel can accommodate and cooperate with the
guide rail rib 32. In the configuration shown in FIG. 1, the
channel 38 in the shroud extends along the whole length of the
shroud 22 in a direction perpendicular to the intended cut
direction and parallel with a plane defined by the base plate.
[0033] FIG. 2 shows the circular saw of FIG. 1 in a so-called door
cutting mode. Of course, this mode of operation is not limited to
undercutting doors; this figure merely illustrates one application,
that of cutting doors.
[0034] Referring to FIG. 2, the circular saw 10 is disposed on a
floor surface FS adjacent to a door D. The door is mounted to a
wall by hinges, in the usual manner. In this configuration it can
be seen that the saw blade is now orientated horizontally and
parallel to the floor surface. The outer surface 36 of the shroud
22 is disposed on the floor FS or a guide rail 30 disposed on the
floor. The channel 38 is shown in cooperation with the rib of the
guide rail. As a result, the saw can be guided along the surface DS
of the door when the guide rail is arranged parallel to the door's
surface DS. Furthermore, the operator can arrange the (now)
vertical base plate 28 to engage with the door's surface so that
the base plate can act as a further guiding means.
[0035] Thus, the blade can cut a portion of the door closest to the
floor along the width of the door. Such an operation is known as
undercutting. The operator is therefore able to remove a lower
portion of the door to provide a greater gap between the base of
the door and the floor surface without removing the door from the
door frame. As a result, a gap between the floor and underside of
the door can be increased to allow a carpet to be laid under the
door, for instance.
[0036] Saw dust or debris is often ejected from or extracted
through an aperture disposed in the blade shroud. In the
embodiments of the present invention, any such aperture (if such an
aperture is provided) should be disposed on an inner surface of the
shroud facing the housing 12. Alternatively, the aperture can be
arranged at the rear of the shroud but in manner which does not
cause a portion of the aperture or aperture housing to protrude
from the flat planar outer surface.
[0037] Referring now to FIG. 3, a portion of the blade shroud 22 is
shown. The shroud comprises inner 40 and outer 42 components which
are spaced apart and joined together by a rubber bellows 44 or
resilient expansion means. The inner portion of the shroud is
mounted to the housing.
[0038] The bellows allow relative movement of the inner and outer
portions. As a result, the distance between the plane of rotation
of the saw blade and the floor surface can be adjusted.
Furthermore, the bellows should not prevent any debris from
escaping the shroud in an unwanted manner--the shroud remains a
closed hood accommodating a portion of the saw blade, save for any
debris extraction means.
[0039] In an alternative arrangement, shown in FIG. 4, the inner
and outer shroud portions comprise over lapping elements, which
provide the same advantages and/or effects described above.
[0040] Both embodiments shown in FIGS. 3 and 4 should also comprise
a means for maintaining the inner and outer component parts of the
shroud in alignment with one another. This is necessary in order to
maintain the alignment of the outer surface, upon which the saw
rests during an undercutting operation, with the plane in which a
saw blade rotates during use. If this alignment is not kept with a
degree of accuracy, the resulting cut to the workpiece can be
undesirably rough-edged. This results in further work having to be
done to the workpiece in order to make good the rough-edged cut.
Such alignment means might take the form of a pin 48 disposed on
the inner portion 40 of the shroud and cooperating with a bore 50
disposed on the outer portion 42 of the shroud. Two or more of
these means might be necessary to ensure accuracy of alignment.
Similar alignment devices will be envisaged by the skilled
person.
[0041] Referring to FIG. 5, a circular saw, having a plunge-action
cut, is shown disposed on a guide rail. The rail is lying parallel
to the door's surface DS and the base plate of the saw is in
engagement with the door's surface. Thus, the saw is guided by both
the guide rail and the door surface.
[0042] Alternative arrangements of the embodiments described above
will be envisaged by the skilled person. For instance, the shroud's
outer surface might not require a channel. An alternative
embodiment might include low-friction strips of material partially
embedded in the outer surface. Such material might comprise nylon
or PTFE. A shim having predetermined thickness could be used to set
the distance between the blade's axis of rotation and the surface
on which the saw is disposed when operating in an undercutting
mode. The shim can be disposable between the shroud and guide rail,
or between the guide rail and floor surface. Several shims of
varying and/or different thickness can be supplied thereby
providing a means to adjust the cut height from the floor within a
combination of distances.
* * * * *